This invention relates to a method of making a packaging tray which consists of outer and inner layers of initially flat blanks of a synthetic plastic material which is moldable when softened and thus stretchable, and intermediate layers of liquid-absorbing material having no or but insignificant stretchability, or in other words substantially non-stretchable said packaging tray having a bottom, side walls formed by stretching of the plastic material, and an outwardly directed flange extending around the rim of the tray.